The Washington Post is tentatively planning to publish for national distribution a tabloid-sized weekly edition early next year.

The weekly would emphasize news of government, politics and economics and would aim at "an audience of people who care most" about those topics, publisher Donald Graham said yesterday.

Company officials said subscription offers were mailed to about 700,000 persons last week. The mailing included a letter from Katharine Graham, Washington Post Co. chairman, describing the weekly as "a history-making new venture in journalism. It is the first time that The Washington Post . . . will be made available to readers everywhere in a specially edited, weekly edition."

Alice Rogoff, assistant to Donald Graham, emphasized that a final decision on whether to proceed with the weekly will depend on response to the mail solicitation. "We have every reason to believe the results will be positive," she said.

The Washington Post National Weekly Edition, a prototype of which already has been shown to sample audiences, would be unlike anything else in American journalism. It would package in magazine format, on heavy paper, a week's selection of in-depth reports on major issues by Post reporters and columnists. The New York Times and The Wall Street Journal distribute their weekday editions nationally on newsstands, but neither offers a weekly selection of its leading articles to selected subscribers.

The new weekly would be distributed mostly by mail, but Rogoff said it also is likely to be made available on selected newsstands, such as those at airports in major cities.

Because the daily Washington Post has limited circulation outside the capital, its reports often have been unavailable to interested readers in business, government and the academic world elsewhere in the country, company officials said.

The National Weekly Edition, according to Donald Graham, "would give readers around the country access to The Post's coverage of government, politics, the economy and diplomatic affairs."

If the decision is made to proceed, distribution is expected to begin in February. The paper will sell for $1 a copy, or $39 for a one-year subscription.

"While we cannot yet predict what its circulation would be, we would expect it to be quite limited by traditional standards," Donald Graham said. "In its early stages, that should mean a circulation of well under 100,000."

The paper will accept advertising.